Method system and apparatus for providing image data in client/server systems

Abstract

A client/server system serves imagery to users with speed, efficiency, and desirable functionality. Clients are allocated the means to determine the image data necessary to generate views on an image. The clients issue requests for such necessary image data to servers who service the requests and send requested image data to the clients who then generate the views. The system responds quickly to changes of views resulting form user actions such as panning or zooming by enabling clients to determine which image data is needed that has not already been served and requesting service of only that data. Clients are also enabled to issue requests to cancel service of data previously requested, but unserved and no longer needed.

We claim:  
     
       1. A method for accessing image data through a server, comprising: 
       receiving successive user requests for views on an image;  
       determining image data necessary for an image drawing site to set a first current view on the image;  
       generating and transmitting a request to a server to cancel the provision of image data that was requested to set a previous view on the image, that is not necessary for the first current view, and that has not been received at the image drawing site; and  
       generating and transmitting a request to the server to provide image data that is necessary to set the first current view on the image but that is not at the image drawing site.  
     
     
       2. The method of  claim 1 , further including generating a portion of the first current view at the image drawing site using image data that is at the image drawing site when request to provide is generated and transmitted. 
     
     
       3. The method of  claim 2 , further including: 
       receiving the requested image data; and  
       generating the first current view using the requested data and the available data.  
     
     
       4. The method of  claim 2 , further including: 
       completing the first current view using the requested data and the available data.  
     
     
       5. The method of  claim 1 , further including: 
       following generating a portion, determining image data necessary for the image drawing site to replace the first current view with a second current view on the image, the image data necessary for the second current view including image data necessary for the first current view;  
       generating and transmitting a request to the server to provide image data that is necessary to set the second current view on the image but is not at the image drawing site;  
       generating and transmitting to the server to cancel the provision of image data that was requested to set the first current view, that is not necessary to set the second current view, and that has not been received at the image drawing site; and  
       generating a portion of the second current view at the image drawing site using image data that was requested to set the first current view and that is at the image drawing site.  
     
     
       6. A client for accessing image data through a server, comprising: 
       an application process for receiving user requests for views on an image;  
       an image drawing process for determining image data necessary to generate a first current view on the image; and,  
       a communications process for generating and transmitting a request to the server to cancel the provision of image data that was requested to set a previous view on the image, that is not necessary for the first current view, and that has not been received by the client, and for generating and transmitting a request to the server to provide image data that is necessary to set the first current view on the image but that is not at the client.  
     
     
       7. The client of  claim 6 , wherein the image drawing process is further for generating a portion of the first current view using image data that is at the client when the request to provide is generated and transmitted. 
     
     
       8. The client of  claim 7 , wherein the communications process is further for receiving the requested image data and the image drawing process is further for generating the first current view using the requested data and the available data. 
     
     
       9. The client of  claim 7 , wherein the image drawing process is further for completing the first current view using the requested data and the available data. 
     
     
       10. A method for serving image data from a server, comprising: 
       receiving a request from a client to open an image;  
       opening the image;  
       receiving from the client a request to provide image data that is necessary to set a first current view on the image;  
       receiving from the client a request to cancel the provision of image data that was requested to set the first current view; and  
       transmitting to the client image data that was requested for the first current view and not cancelled.  
     
     
       11. A method of  claim 10 , further including: 
       preventing the acquisition from storage of image data for which a request to cancel was received; or,  
       preventing the transmission to the client of image data acquired from storage and for which a request to cancel has been received.  
     
     
       12. A server for serving image data to a client, comprising: 
       a communications process for receiving a request from a client to open an image;  
       the communications process further for receiving from the client a request to provide image data for a first view on the image, and for receiving a request to cancel the provision of image data that was requested for the first current view and not cancelled; and  
       storage access means for providing to the communications process image data from storage.  
     
     
       13. The server of  claim 12 , further including means for preventing the storage access means from acquiring image data for which a request to cancel was received, and means for preventing the communications process from transmitting to the client image data acquired from storage and for which a request to cancel has been received. 
     
     
       14. A method for processing image data in a client/server system in which image data is stored in a server and views on images are generated by clients, comprising: 
       determining image data requested for generating views on an image at a client; and  
       streaming requests from the client to a server for units of image data to generate the views, the requests including requests to provide image data which is necessary to generate a current view at the client but which is not at the client and results to cancel the provision of image data previously requested, but not received, by the client.  
     
     
       15. The method of  claim 12 , further including streaming requests to the server from a plurality of clients for provision of image data and requests for cancellation image data.